Its hard to speculate, but what i've seen about your opninions, its strange that Leonardo came out and sets him self in that position. His new movie, The Aviator is very promising, and it appears he likes these some what smaller scale movies, old school.

It might be due to the reason that he wants to be accepted as the multiple role, medium sized block buster success: over and over again. Now what happend in titanic is 1 big hit which rather came as a surprise as james cameron tried to get the budget deficit crisis fixed with the management and what, viola top grossing, oscar prince and what else not. Now his name is associated and on the top of this titnanic movie, so hard to change the image surrounding him self.

It doesn't look like it is about the money, he just bought a big apartment in las vegas, to spend money with betting, and he earned alot long shot already. but i can also imagine it is something to do politically with the fact that james cameron has made a 3d imax titanic movies like ghost of the abyss and never seems to stop about doing the titanic subject, so by this bad fame thing he might be trying to water down the association he has with titanic for these kind of reason...